Proper collection, containment, control, transportation and disposal of solid waste are necessary for protecting public health and safety and for promoting a clean environment. Containers, commonly known as dumpsters, that hold large quantities of solid waste generated at multifamily residential, institutional, commercial, industrial, and construction sites, are an important tool in the management of solid waste.
There are at least two types of dumpsters for handling solid waste, the "front loader" dumpster and the "rear loader" dumpster. Present dumpster designs incorporate several common features including: a floor, side walls, and end walls which together define an interior compartment; openings through which solid waste is placed into the interior compartment; openings through which the solid waste is discharged out of the interior compartment; and means for supporting the dumpster while the solid waste is being discharged.
The front loader type dumpster is typically used at multifamily residential and light commercial sites and is provided with sleeves fixed to the exterior of the side walls to receive the lifting arms of a front loading truck. The front loading truck approaches the front loader dumpster and positions the arms of the truck within the sleeves of the container. The driver then activates a hydraulic system which lifts the dumpster over the cabin of the truck and rotates it to a substantially inverted position to discharge the solid waste into a larger container on the back of the truck, generally referred to as a hopper. Next, the driver lowers the empty dumpster and withdraws the lifting arms of the front loading truck from the sleeves. The driver may then activate a compactor in the hopper to compact the solid waste and thereby increase the amount of solid waste that the hopper can accommodate. The front loading truck then travels to the location of the next front loader dumpster to repeat the procedure until the hopper is full. Once the hopper is full, the front loading truck travels to a disposal site, such as a landfill, to dispose of the solid waste.
The rear loader type dumpster is larger than a front loader type dumpster and is typically used at heavy commercial, industrial and construction sites. Rather than being emptied into the hopper of a front loading truck, the rear loader dumpster is pulled onto the bed of a roll-off truck and transported to the disposal site. A typical roll-off truck is equipped with a winch and roller system which positions the dumpster onto the bed of the truck for transportation to the disposal site. Once at the disposal site, the bed and dumpster are tilted so that the solid waste is discharged through one or more rear doors provided in the end wall of the dumpster, much like a dump truck. After being emptied, the rear loader dumpster is returned to the same or a different refuse collection site.
Utilizing different types of dumpsters which each require a different method of discharging the solid waste reduces both the cost effectiveness and the efficiency of solid waste collection. Conventional front loader type dumpsters are relatively small and are not provided with a door in an end wall of the dumpster. Furthermore, because the solid waste in a conventional front loader dumpster must be discharged through an opening in the top of the dumpster, it cannot be emptied by a roll-off truck. Conventional rear loader type dumpsters are wider than front loader type dumpsters and are not provided with sleeves. As such, a rear loader dumpster cannot be emptied by a front loading truck. Accordingly, solid waste collection would be more cost effective and efficient if the two types of dumpsters could be combined into a single universal dumpster which can be emptied by either a front loading truck or a roll-off truck.
A major environmental concern is the accidental dispersal of solid waste from a front loader dumpster while the solid waste is being discharged into the hopper of the front loading truck. For example, a sudden gust of wind may disperse some of the solid waste onto the ground surrounding the front loading truck as the front loader dumpster is being emptied. Front loader dumpsters are discharged at refuse collection sites which are typically located in areas where people live and work. Thus, the solid waste that is accidentally dispersed has a negative impact on both the public health and safety and the environment.
Conventional designs for front loader dumpsters pose additional safety concerns. The sleeves of a front loader dumpster that engage the lifting arms of a front loading truck are typically welded onto the exterior surface of the side walls of the dumpster. Because the solid waste in a conventional front loader dumpster is discharged through an opening in the top, the dumpster must be completely inverted to discharge all of the solid waste from the interior compartment. Completely inverting the dumpster induces shock stresses on the welds holding the sleeves to the side walls because the weight of the dumpster suddenly shifts from the top of the sleeves to the bottom of the sleeves as the dumpster is inverted. Over time, the welds holding the sleeves to the side walls can weaken and ultimately break from repeated emptying of the dumpster. As a result, the dumpster could fall onto the front loading truck as it is being inverted to discharge the solid waste, potentially injuring workers or passersby.
In addition to posing a safety hazard, the shock stresses induced on the sleeve welds reduce the efficiency of front loading trucks. The lifting capability of late model front-loading trucks usually exceeds the weight capacity of a front loader dumpster. However, because of the danger of the sleeves breaking away from the side walls, the usable volume of a front loader dumpster is limited by a safety factor. If front loader dumpsters were provided with doors in one of the end walls for discharging solid waste, they would not have to be completely inverted to discharge all of the solid waste from the interior compartment of the dumpster. Eliminating the need to completely invert the dumpster would eliminate the shock stresses on the welds holding the sleeves to the side walls induced by the sudden shifting of the weight of the dumpster on the sleeves. As a result, dumpsters capable of containing a larger volume of solid waste could be utilized with front loading trucks.
For the foregoing reasons, it is apparent that a need exists for a universal dumpster that can be emptied by either a front loading truck or a roll-off truck. A need also exists for a universal dumpster which minimizes, and preferably eliminates, the accidental dispersal of solid waste into the environment during discharge of the solid waste into the hopper of a front loading truck. Finally, there exists a need to increase both the safety of front loader dumpsters and the efficiency of front loading trucks.